tty

TTY(4)			  Linux Programmer’s Manual		       TTY(4)



NAME
       tty - controlling terminal

DESCRIPTION
       The  file  /dev/tty  is a character file with major number 5 and minor
       number 0, usually of mode 0666 and owner.group root.tty.	 It is a syn-
       onym for the controlling terminal of a process, if any.

       In  addition  to the ioctl() requests supported by the device that tty
       refers to, the ioctl() request TIOCNOTTY is supported.

   TIOCNOTTY
       Detach the current process from its controlling terminal.

       If the process is the session leader, then SIGHUP and SIGCONT  signals
       are sent to the foreground process group and all processes in the cur-
       rent session lose their controlling tty.

       This  ioctl()  call  only  works	 on  file  descriptors	connected  to
       /dev/tty.  It  is  used by daemon processes when they are invoked by a
       user at a terminal.  The process attempts to  open  /dev/tty.  If  the
       open  succeeds,	it  detaches  itself from the terminal by using TIOC-
       NOTTY, while if the open fails, it is obviously not attached to a ter-
       minal and does not need to detach itself.

FILES
       /dev/tty

SEE ALSO
       mknod(1),   chown(1),   getty(1),  ioctl(2),  termios(3),  console(4),
       ttys(4)



Linux				  2003-04-07			       TTY(4)